Gramophone needle sharpener



June 26, 1934.

A. F. J. WRIGHT GRAMOPHONE NEEDLE SHARPENER Filed March 24, 1932 ZZM W Ava/My Patented June 26, 1934 UNITED STATES PATENT OFFICE England Application March 24, 1932, Serial No. 601,021 .In Great Britain June 6, 1931 .1 Claim.

An application has been filed in Great Britain June 6, 1931.

This invention relates to devices for sharpening gramophone needles, small tools and the like ,5 and is particularly applicable to the sharpening of gramophone needles of relatively soft material such as fibre needles and needles of similar materials which are now coming into extensive use. The invention is in fact an improvement in or modification of that set forth in the specification of my United States patent application No. 490,728, filed 23rd October, 1930 now Patent No. 1,851,229, dated March 29, 1932. In the said prior specification a sharpening device is set forth having a rotatably mounted abrasive wheel and a holder for the object to be sharpened. The abrasive wheel was to be positively driven through hand-operating means and to be yieldingly pressed into contact with the needle which was itself rotated with its holder by frictional contact with a member driving the abrasive wheel. The object of the present invention is to produce a hand-operated device of the same kind, which has the additional advantage of allowing the pressure between the object to be sharpened and the abrasive to be always under the control of the operator. Further, the improved construction is considerably simplified and, therefore, can be manufactured very much more cheaply.

According to the invention, the improved sharpening device for gramophoneneedles, small tools and the like has an abrasive disc directly driven by hand and mounted for this purpose on a spindle provided with a degree of axial freedom so that the pressure between the object to be sharpened which is rotated in contact with the abrasive disc and the abrasive disc itself is under the control of the operator. The sharpening device is most conveniently driven by frictional contact and the drive is preferably ob tained by frictional contact between the holder and a disc mounted on and to rotate with the spindle.

In order that the invention may be thoroughly understood and more readily carried into effect, an example of construction in accordance therewith will now be described with reference to the accompanying drawing, in which:

Figure l is an elevation of the improved sharpener;

Figure 2 is a view taken in the direction of the arrow II in Figure 1;

Figure 3 is a section taken on the line III-III 55 of Figure 1, and

Figure 4 is a section taken on the line IVIV of Figure 1.

All the parts of the sharpener are carried by a metal stamping 1 having turned-up lugs 2, which are gripped by the fingers when the de- 50 vice is in use. This stamping 1 is also provided with a freely mounted hollow boss 3 which provides a bearing for a spindle 4. The latter has a crank 5 at one end and a disc 6 at the other. An abrasive disc 7 is held to the face of the disc 5 6 by means of a nut 8 so that it can be rotated by the crank 5.

The stamping 1 also has a projecting piece 9 to which the needle holder assembly is pivoted on the pin 10. The needle holder assembly consists of a chuck 11 and a chuck holder 12, which is provided with a rubber band or tyre 13 bearing against the face of a disc 14 mounted on the boss 3 between the disc 6 and the stamping 1. This disc 14 is rotated with the disc '6 by means of a pin 15 (see Figure 4) fixed to the disc 6 and passing through a suitable hole in the disc 14.

Thus when the crank 5 is rotated the abrasive disc '7 and the disc 14 are rotated and the chuck l1 and chuck holder 12 are also rotated by means of the friction between the tyre 13 and the disc 14 which are urged into contact with each other by a blade spring 16 fixed to the stamping 1 and bearing on the end 17 of the chuck holder assembly. The needle 18 is thus rotated in contact with the rotating abrasive disc 7.

It will be seen from the drawing that the length of the spindle 4 is such as to allow it a certain amount of lengthwise play so that as the crank 5 is turned by hand the abrasive disc '7 can be urged into contact more or less strongly with the needle 18 so as to obtain the desired amount of grinding. The position taken up by the various parts when the spindle 4 is pressed forward is shown in dotted lines in Figure 4. Thus the grinding operation is entirely under control, the speed and pressure being controlled at the same time by the hand that turns the crank 5.

The split chuck 11 shown in the drawing has the advantage that the needle can be inserted quickly and conveniently. A number of these chucks to suit different diameters and shapes of needles can be provided. The more usual chuck having a thumb screw for holding the needle could, of course, equally well be used. The abrasive disc 7 may be of sand paper, emery paper or any other suitable material and the disc 14 may, if desired, be surfaced so as to increase the friction between it and the chuck holder 12.

It will be noted that with the described arin said frame and movable by hand towards and away therefrom, a rotatable disc coaxial with said disc and adapted to be driven thereby, a holder for the object to be pointed in rotational engagement with said disc and means for rotating said abrasive disc while urging it into contact with said object.

ALBERT FREDERICK JAIVIES WRIGHT.

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